New Atheism lends itself to, and often overlaps with, secular humanism and antitheism—most particularly, in its criticism of what many New Atheists regard as the indoctrination of children and the perpetuation of ideologies founded on belief in the supernatural. Some critics of the movement characterize it as "militant atheism" or "fundamentalist atheism".[a][6][7][8][9]

The Harvard botanist Asa Gray, a believing Christian and one of the first supporters of Charles Darwin's theory of evolution, commented in 1868 that the more worldly Darwinists in England had "the English-materialistic-positivistic line of thought".[10] Darwin's supporter Thomas Huxley was openly skeptical, as the biographer Janet Browne describes:

Huxley was rampaging on miracles and the existence of the soul. A few months later, he was to coin the word "agnostic" to describe his own position as neither a believer nor a disbeliever, but one who considered himself free to inquire rationally into the basis of knowledge, a philosopher of pure reason [...] The term fitted him well [...] and it caught the attention of the other free thinking, rational doubters in Huxley's ambit, and came to signify a particularly active form of scientific rationalism during the final decades of the 19th century. [...] In his hands, agnosticism became as doctrinaire as anything else--a religion of skepticism. Huxley used it as a creed that would place him on a higher moral plane than even bishops and archbishops. All the evidence would nevertheless suggest that Huxley was sincere in his rejection of the charge of outright atheism against himself. He refused to be "a liar". To inquire rigorously into the spiritual domain, he asserted, was a more elevated undertaking than slavishly to believe or disbelieve. "A deep sense of religion is compatible with the entire absence of theology," he had told [Anglican clergyman] Charles Kingsley back in 1860. "Pope Huxley", the [magazine] Spectator dubbed him. The label stuck." —Janet Browne[11]

In a 2010 column entitled "Why I Don't Believe in the New Atheism", Tom Flynn contends that what has been called "New Atheism" is neither a movement nor new, and that what was new was the publication of atheist material by big-name publishers, read by millions, and appearing on bestseller lists.[16]

On 6 November 2015, the New Republic published an article entitled, "Is the New Atheism dead?"[17] The atheist and evolutionary biologist David Sloan Wilson wrote, "The world appears to be tiring of the New Atheism movement."[18] In 2017, PZ Myers who formerly considered himself a new atheist, publicly renounced the New Atheism movement.[19]

The book The Four Horsemen: The Conversation That Sparked an Atheist Revolution was released in 2019.[20]

Christopher Hitchens was the author of God Is Not Great[29] and was named among the "Top 100 Public Intellectuals" by Foreign Policy and Prospect magazines. In addition, Hitchens served on the advisory board of the Secular Coalition for America. In 2010 Hitchens published his memoir Hitch-22 (a nickname provided by close personal friend Salman Rushdie, whom Hitchens always supported during and following The Satanic Verses controversy).[30] Shortly after its publication, Hitchens was diagnosed with esophageal cancer, which led to his death in December 2011.[31] Before his death, Hitchens published a collection of essays and articles in his book Arguably;[32] a short edition Mortality[33] was published posthumously in 2012. These publications and numerous public appearances provided Hitchens with a platform to remain an astute atheist during his illness, even speaking specifically on the culture of deathbed conversions and condemning attempts to convert the terminally ill, which he opposed as "bad taste".[34][35]

After the death of Hitchens, Ayaan Hirsi Ali (who attended the 2012 Global Atheist Convention, which Hitchens was scheduled to attend) was referred to as the "plus one horse-woman", since she was originally invited to the 2007 meeting of the "Horsemen" atheists but had to cancel at the last minute.[40] Hirsi Ali was born in Mogadishu, Somalia, fleeing in 1992 to the Netherlands in order to escape an arranged marriage.[41] She became involved in Dutch politics, rejected faith, and became vocal in opposing Islamic ideology, especially concerning women, as exemplified by her books Infidel and The Caged Virgin.[42]

Hirsi Ali was later involved in the production of the film Submission, for which her friend Theo Van Gogh was murdered with a death threat to Hirsi Ali pinned to his chest.[43] This event resulted in Hirsi Ali's hiding and later immigration to the United States, where she now resides and remains a prolific critic of Islam.[44] She regularly speaks out against the treatment of women in Islamic doctrine and society[45] and is a proponent of free speech and the freedom to offend.[46][47]

Many contemporary atheists write from a scientific perspective. Unlike previous writers, many of whom thought that science was indifferent or even incapable of dealing with the "God" concept, Dawkins argues to the contrary, claiming the "God Hypothesis" is a valid scientific hypothesis,[51] having effects in the physical universe, and like any other hypothesis can be tested and falsified. The late Victor Stenger proposed that the personal Abrahamic God is a scientific hypothesis that can be tested by standard methods of science. Both Dawkins and Stenger conclude that the hypothesis fails any such tests,[52] and argue that naturalism is sufficient to explain everything we observe. Nowhere, they argue, is it necessary to introduce God or the supernatural to understand reality. Some New Atheists adhere to the fringe Christ myth theory.[53]

Richard Dawkins has been particularly critical of the conciliatory view that science and religion are not in conflict, noting, for example, that the Abrahamic religions constantly deal in scientific matters. In a 1998 article published in Free Inquiry magazine[54] and later in his 2006 book The God Delusion, Dawkins expresses disagreement with the view advocated by Stephen Jay Gould that science and religion are two non-overlapping magisteria (NOMA), each existing in a "domain where one form of teaching holds the appropriate tools for meaningful discourse and resolution".

In Gould's proposal, science and religion should be confined to distinct non-overlapping domains: science would be limited to the empirical realm, including theories developed to describe observations, while religion would deal with questions of ultimate meaning and moral value. Dawkins contends that NOMA does not describe empirical facts about the intersection of science and religion: "It is completely unrealistic to claim, as Gould and many others do, that religion keeps itself away from science's turf, restricting itself to morals and values. A universe with a supernatural presence would be a fundamentally and qualitatively different kind of universe from one without. The difference is, inescapably, a scientific difference. Religions make existence claims, and this means scientific claims."

Popularized by Sam Harris is the view that science and thereby currently unknown objective facts may instruct human morality in a globally comparable way. Harris' book The Moral Landscape[61] and accompanying TED Talk How Science can Determine Moral Values[62] propose that human well-being and conversely suffering may be thought of as a landscape with peaks and valleys representing numerous ways to achieve extremes in human experience, and that there are objective states of well-being.

New Atheism is politically engaged in a variety of ways. These include campaigns to draw attention to the biased, privileged position religion has and to reduce the influence of religion in the public sphere, attempts to promote cultural change (centering, in the United States, on the mainstream acceptance of atheism), and efforts to promote the idea of an "atheist identity". Internal strategic divisions over these issues have also been notable, as are questions about the diversity of the movement in terms of its gender and racial balance.[63]

The theologians Jeffrey Robbins and Christopher Rodkey take issue with what they regard as "the evangelical nature of the New Atheism, which assumes that it has a Good News to share, at all cost, for the ultimate future of humanity by the conversion of as many people as possible." They believe they have found similarities between New Atheism and evangelical Christianity and conclude that the all-consuming nature of both "encourages endless conflict without progress" between both extremities.[64]

Sociologist William Stahl said, "What is striking about the current debate is the frequency with which the New Atheists are portrayed as mirror images of religious fundamentalists."[65]

The atheist philosopher of scienceMichael Ruse has made the claim that Richard Dawkins would fail "introductory" courses on the study of "philosophy or religion" (such as courses on the philosophy of religion), courses which are offered, for example, at many educational institutions such as colleges and universities around the world.[66][67] Ruse also claims that the movement of New Atheism—which is perceived, by him, to be a "bloody disaster"—makes him ashamed, as a professional philosopher of science, to be among those holding to an atheist position, particularly as New Atheism does science a "grave disservice" and does a "disservice to scholarship" at more general level.[66][67]

Paul Kurtz, editor in chief of Free Inquiry, founder of Prometheus Books, was critical of many of the new atheists.[8] He said, "I consider them atheist fundamentalists... They're anti-religious, and they're mean-spirited, unfortunately. Now, there are very good atheists and very dedicated people who do not believe in God. But you have this aggressive and militant phase of atheism, and that does more damage than good".[9]

Jonathan Sacks, author of The Great Partnership: Science, Religion, and the Search for Meaning, feels the new atheists miss the target by believing the "cure for bad religion is no religion, as opposed to good religion". He wrote:

Atheism deserves better than the new atheists whose methodology consists of criticizing religion without understanding it, quoting texts without contexts, taking exceptions as the rule, confusing folk belief with reflective theology, abusing, mocking, ridiculing, caricaturing, and demonizing religious faith and holding it responsible for the great crimes against humanity. Religion has done harm; I acknowledge that. But the cure for bad religion is good religion, not no religion, just as the cure for bad science is good science, not the abandonment of science.[68]

The philosopher Massimo Pigliucci contends that the new atheist movement overlaps with scientism, which he finds to be philosophically unsound. He writes: "What I do object to is the tendency, found among many New Atheists, to expand the definition of science to pretty much encompassing anything that deals with 'facts', loosely conceived..., it seems clear to me that most of the New Atheists (except for the professional philosophers among them) pontificate about philosophy very likely without having read a single professional paper in that field.... I would actually go so far as to charge many of the leaders of the New Atheism movement (and, by implication, a good number of their followers) with anti-intellectualism, one mark of which is a lack of respect for the proper significance, value, and methods of another field of intellectual endeavor."[69]

Atheist professor Jacques Berlinerblau has criticised the New Atheists' mocking of religion as being inimical to their goals and claims that they have not achieved anything politically.[70]

Roger Scruton has extensively criticized New Atheism on various occasions, generally on the grounds that they do not consider the social effects and impacts of religion in enough detail. He has said, "Look at the facts in the round and it seems likely that humans without a sense of the sacred would have died out long ago. For that same reason, the hope of the new atheists for a world without religion is probably as vain as the hope for a society without aggression or a world without death." He has also complained of the New Atheists' idea that they must "set people free from religion", calling it "naive" because they "never consider that they might be taking something away from people."[71][72]

^"New Atheists". The Internet Encyclopedia of Philosophy. Retrieved 14 April 2016. The New Atheists are authors of early twenty-first century books promoting atheism. These authors include Sam Harris, Richard Dawkins, Daniel Dennett, and Christopher Hitchens. The 'New Atheist' label for these critics of religion and religious belief emerged out of journalistic commentary on the contents and impacts of their books.

^ abDe Waal, Frans (25 March 2013). "Has militant atheism become a religion?". Salon.com. Retrieved 9 March 2017. Why are the 'neo-atheists' of today so obsessed with God's nonexistence that they go on media rampages, wear T-shirts proclaiming their absence of belief, or call for a militant atheism? What does atheism have to offer that's worth fighting for? As one philosopher put it, being a militant atheist is like 'sleeping furiously.'

^"The Four Horsemen DVD". Richard Dawkins Foundation. Retrieved 13 April 2016. On the 30th of September 2007, Richard Dawkins, Daniel Dennett, Sam Harris and Christopher Hitchens sat down for a first-of-its-kind, unmoderated 2-hour discussion, convened by RDFRS and filmed by Josh Timonen.

^Hoffman, Claire (2 September 2014). "Sam Harris is Still Railing Against Religion". Los Angeles Magazine. Retrieved 13 April 2016. As Western society grappled with radical Islam, Harris distinguished himself with his argument that modern religious tolerance had placated us into allowing delusion rather than reason to prevail. Harris upended a discussion that had long been dominated by cultural relativism and a hands-off academic intellectualism; his seething contempt for the world's faiths helped launch the 'New Atheist' movement, and together with Christopher Hitchens, Richard Dawkins, and Daniel Dennett, he became known as one of the 'Four Horsemen of the Non-Apocalypse.'

^Stedman, Chris (18 October 2010). "'Evangelical Atheists': Pushing For What?". The Huffington Post. Retrieved 2 March 2017. something peculiarly evangelistic about what has been termed the new atheist movement ... It is no exaggeration to describe the movement popularized by the likes of Richard Dawkins, Daniel Dennett, Sam Harris, and Christopher Hitchens as a new and particularly zealous form of fundamentalism — an atheist fundamentalism.

^Jeffrey Robbins and Christopher Rodkey (2010). "Beating 'God' to Death: Radical Theology and the New Atheism". In Amarnath Amarasingam (ed.). Religion and the New Atheism A Critical Appraisal. Haymarket Books. p. 35. ISBN9781608462032.

^William Stahl (2010). "One-Dimensional Rage: The Social Epistemology of the New Atheism and Fundamentalism". In Amarnath Amarasingam (ed.). Religion and the New Atheism A Critical Appraisal. Haymarket Books. pp. 97–108. ISBN9781608462032.

^ abDougherty, T; Gage, LP (2015). "4/ New Atheist Approaches to Religion, pp. 51-62". In Oppy, Graham (ed.). The Routledge Handbook of Contemporary Philosophy of Religion. Oxon and New York: Routledge. pp. 52–53. ISBN9781844658312. Michael Ruse (2009) claimed that Dawkins would fail 'any philosophy or religion course'; and for this reason Ruse says The God Delusion made him 'ashamed to be an atheist'

^ abRuse, Michael (August 2009). "Why I Think the New Atheists are a Bloody Disaster". Beliefnet. The BioLogos Foundation as a columnist of Beliefnet. Retrieved 19 August 2015. … the new atheists do the side of science a grave disservice … these people do a disservice to scholarship ... Richard Dawkins in The God Delusion would fail any introductory philosophy or religion course. Proudly he criticizes that whereof he knows nothing … the poor quality of the argumentation in Dawkins, Dennett, Hitchens, and all of the others in that group … the new atheists are doing terrible political damage to the cause of Creationism fighting. Americans are religious people ... They want to be science-friendly, although it is certainly true that many have been seduced by the Creationists. We evolutionists have got to speak to these people. We have got to show them that Darwinism is their friend not their enemy We have got to get them onside when it comes to science in the classroom. And criticizing good men like Francis Collins, accusing them of fanaticism, is just not going to do the job. Nor is criticizing everyone, like me, who wants to build a bridge to believers – not accepting the beliefs, but willing to respect someone who does have them … The God Delusion makes me ashamed to be an atheist … They are a bloody disaster …

^Sacks, Jonathan (2011). The Great Partnership: Science, Religion, and the Search for Meaning. New York: Schocken. p. 11. ISBN978-0-805-24301-7.

^Pigliucci, Massimo (2013). New Atheism and the Scientistic Turn in the Atheism Movement. Midwest Studies in Philosophy. pp. 151–152.